单索面斜拉桥剪力滞效应

SHEAR LAG EFFECT ON CABLE-STAYED BRIDGE WITH SINGLE CABLE PLANE

利用能量变分法，求解单索面单室梯形箱梁室内带加劲斜撑的截面的剪力滞效应。单索面斜拉桥承受弯矩与轴力的共同作用，根据小变形理论与叠加原理。将弯矩与轴力分开处理，然后将两者算出的应力叠加，得到综合应力。将综合应力除以σ＝Ｎ／Ａ＋Ｍ／Ｗ，即得到剪力滞综合系数。文中假定纵向位移在截面中心最大并按二次抛物线变化。在弯矩作用下，按四次抛物线规律。通过变分法得到两组微分方程与边界条件，并对微分方程的求解及边界条件进行深入讨论。

By aid of variation approach and energy principle, shear lag effect of trapezoidal box section reinforced with inclined struts in the cell of single plane cable-stayed bridge has been analyzed obviously, moment shear, and thrust are coexisted in section of single-plane cable-stayed bridge. According to small deflection theory and principle of superposition, the normal stress due to bending and axial force may be treated separately. The combined stress induced by moment and thrust can be added to get the combined stress effect. The coefficient of shear lag can be computed from combined stress divided by , where = N/A + M/W. In this paper, assumptions are made with spanwise deformation following the parabolic variation and reaching maximum at center of cross section, meanwhile under the moment, the longitudinal displacement follows quartic parabo la. Through variation approach and energy principle, two sets of governing differential equation and boundary conditions are finally obtained. Fully discussions are made with solution on differential equations and boundary conditions.